Lazer Z (hard to find problem) engine stalls after bumps

My Lazer Z hesitates or loses power when you hit a hard bump. It is a Kohler 27 hp with only 50 hrs on it and it only hesitates for less than a second. Then resumes at full power. The best that Exmark could guess is that I may have a bad safety switch. I by passed the switch on the seat but it still does it. This would be a hard thing for a dealer to track down since it doesn't do it all the time and actually doesn't hurt my mowing its just a little agravating for a new mower. Could it be a carb problem? Or do you think it would be in a safety switch? Any other ideas? I doubt my dealer would ever be able to find it since it only does it every now and then. Its seems like the fuel is shut off for an instant after it hits a bump. All replies welcome. I hate to replace every switch only to find out its something else.

My Lazer Z hesitates or loses power when you hit a hard bump. It is a Kohler 27 hp with only 50 hrs on it and it only hesitates for less than a second. Then resumes at full power. The best that Exmark could guess is that I may have a bad safety switch. I by passed the switch on the seat but it still does it. This would be a hard thing for a dealer to track down since it doesn't do it all the time and actually doesn't hurt my mowing its just a little agravating for a new mower. Could it be a carb problem? Or do you think it would be in a safety switch? Any other ideas? I doubt my dealer would ever be able to find it since it only does it every now and then. Its seems like the fuel is shut off for an instant after it hits a bump. All replies welcome. I hate to replace every switch only to find out its something else.

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Could be a carb problem, i had some dixies that did that after cleaning the carb it would get better. If it really get to you.... you may want to switch to a EFI engine.

When the motor hesitiates or loses power, does it "stumble" or does it complete stop firing for a second or two? If it stumbles, then it most likely is a fuel problem (not absolutely, but likely). If it completely stops firing, then it is most likely an electrical "thing." I too have had a similar thing happen, but it turns out my butt bounces off the seat briefly. The motor sounds like a "high speed" miss and immediatly catches, and I continue on. Sometimes, mine will cut out if I roll over onto the side of the seat. In my case, I didn't want to by-pass the operator seat switch, so I slow down for the bigger bumps. You might test it by quickly raising off the seat to see if it sounds the same as when it happens while you are mowing.

I've had similar problems with my mowers. Both times it's been electrical, and the mechanics at the dealership were absolutely no help at all. Before paying them your hard earned money go over the entire electrical system yourself. Look for any loose connections, connectors which are discolored due to grounding out, make sure battery terminals are tight, look for exposed wire near metal, make sure wires going into quick connectors aren't loose, and make sure all the screws securing wires (on motor and control panel) are tight. After doing all that, if the problem remains, then try bypassing the safety switches one by one.